Hello. I have a problem running this code under linux 2.4.3: the
"recv" function does not block, but instead returns "0". The same code
under linux 2.2.19 will block until a datagram is received. I think
the problem is in the shutdown code (although the socket is not
connected). Any idea?
#include <unistd.h>
#include <stdio.h>
#include <netinet/in.h>
#include <sys/types.h>
#include <sys/socket.h>
int main(void)
{
int so, so2, res;
struct sockaddr_in peer;
unsigned char buffer[1024];
so = socket(AF_INET, SOCK_DGRAM, 0);
memset(&peer, 0, sizeof(peer));
bind(so, &peer, sizeof(peer));
so2 = dup(so);
/* receive disallowed. Returns -1 = ENOTCONN */
/* Does shutdown refer both to so and so2? */
shutdown(so, 0);
/* Under linux 2.4.3 this will not block, and it will return 0
(success!).
Under 2.2.19, this will block */
res = recv(so2, buffer, sizeof(buffer), 0);
printf("Result = %d\n", res);
return 0;
}
/************** Under 2.4.3 */
// socket(PF_INET, SOCK_DGRAM, IPPROTO_IP) = 3
// bind(3, {sin_family=AF_UNSPEC, {sa_family=0, sa_data="\0\0\0\0\0\0\0\0\0\0\0\0\0\0"}, 16) = 0
// dup(3) = 4
// shutdown(3, 0 /* receive */) = -1 ENOTCONN (Transport endpoint is not connected)
// recv(4, "", 1024, 0) = 0
--
Salu2
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